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Oksanka [162]
3 years ago
5

Solve the systems by the addition method x - 2y = - 4 2x + y = 7

Mathematics
1 answer:
vfiekz [6]3 years ago
5 0
<h2>x - 2y = -4</h2><h2>2x + y = 7</h2><h2 />

To solve this system of equations by addition, our first goal is to cancel

out one of the variables by adding the two equations together.

However, if we add these two equations together right away, nothing

will cancel so we need to set things up so a variable will cancel.

Notice that we have an 2x in our second equation.

If we had a -2x in our first equation, then the x's would cancel out.

In order to create a -2x in the first equation, we simply

multiply both sides of the first equation by -2.

So we have (-2)(x - 2y) = (-4)(-2) which can be rewritten as -2x + 4y = 8.

Now rewrite both equations, as shown below.

<h2>-2x + 4y = 8</h2><h2>2x + y = 7</h2><h2 />

Now when we add the equations together, the x terms

will cancel out and we're left with 5y = 15.

Dividing both sides by 5, <em>y = 3</em>.

To solve for x, plug a 3 in for y in either one of our 2 original equations.

So let's go with our second equation.

Plugging a 3 in for y, we get 2x + (3) = 7.

Now subtract 4 from both sides to get 2x = 4.

Dividing both sides by 2, we fid that <em>x = 2</em>.

Since x = 2 and y = 3, our answer is the ordered pair (2, 3).

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3 years ago
Maria earns $80 per day working at a gas station. Write an algebraic expression to represent the amount of money she will earn i
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The algebraic expression is 80d

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The algebraic expression is 80d

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A town has 300 residents in total, of which 5/6 are white/Caucasian Americans. How many white/Caucasian Americans reside in this
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Pentagon ABCDE and pentagon A″B″C″D″E″ are shown on the coordinate plane below:
erastova [34]

The transformations that are applied to pentagon ABCDE to create A"B"C"D"E" are:

1) Translation (x, y) → (x + 8, y + 2)

2) Reflection across the x-axis (x, y) → (x, -y)

So, the overall transformation given in the graph is (x, y) → {(x + 8), -(y + 2)}.

<h3>What are the transformation rules?</h3>

The transformation rules are:

  • Reflection across x-axis: (x, y) → (x, -y)
  • Reflection across y-axis: (x, y) → (-x, y)
  • Translation: (x, y) → (x + a, y + b)
  • Dilation: (x, y) → (kx, ky)

<h3>Calculation:</h3>

The pentagons in the graph have vertices as

For the pentagon ABCDE: A(-4, 5), B(-6, 4), C(-5, 1), D(-2, 2), and (-2, 4)

For the pentagon A"B"C"D"E": A"(4, -7), B"(2, -6), C"(3, -3), D"(6, -4), and E"(6, -6)

Consider the vertices A(-4, 5) from the pentagon ABCDE and A"(4, -7) from the pentagon A"B"C"D"E".

Applying the Translation rule for the pentagon ABCDE:

The rule is (x, y) → (x + a, y + b)

So, the variation is

-4 + a = 4

⇒ a = 4 + 4 = 8

5 + b = 7

⇒ b = 7 - 5 = 2

So, the pentagon ABCDE is translated by (x + 8, y + 2).

Applying the Reflection rule for the translated pentagon:

The translated pentagon has vertices (x + 8, y + 2).

When applying the reflection across the x-axis,

(x + 8, y + 2) → {(x + 8), -(y + 2)}

Therefore, the complete transformation of the pentagon ABCDE to the pentagon A"B"C"D"E" is (x, y) → {(x + 8), -(y + 2)}

Verification:

A(-4, 5) → ((-4 + 8), -(5 + 2)) = (4, -7)A"

B(-6, 4) → ((-6 + 8), -(4 + 2)) = (2, -6)B"

C(-5, 1) → ((-5 + 8), -(1 + 2)) = (3, -3)C"

D(-2, 2) → ((-2 + 8), -(2 + 2)) = (6, -4)D"

E(-2, 4) → ((-2 + 8), -(4 + 2)) = (6, -6)E"

Learn more about transformation rules here:

brainly.com/question/4289712

#SPJ1

5 0
2 years ago
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